How Many Solar Panels Do You Need to Charge Your EV?

The number of solar panels needed to charge an electric vehicle (EV) depends on several factors, including your vehicle’s energy efficiency, how far you drive each day, and the amount of sunlight your location receives. 

Charging your EV with solar power is a major step towards decreasing your carbon footprint and living more sustainably. EVs are only as green as the electricity charging their batteries, and pairing your EV with a solar panel system helps to ensure that  your car is powered by renewable energy rather than grid power, which is oftend dominated by fossil fuels and other non-renewable sources. With driving and electricity being two everyday activities that significantly impact our carbon footprint, you’ll also be making your lifestyle a lot more greener – all while maximizing cost savings. 

But how many solar panels do you need to fully charge an EV? The answer depends on manyfactors, which we’ll cover in this guide. Keep reading to learn the benefits of charging electric vehicles with solar power, how much energy your EV needs to charge, how many solar panels you need to fully charge your EV, and more. 

Key takeaways: 

• Charging your EV with solar panels can maximize cost savings, make your EV more sustainable, reduce strain on your home’s electrical system, and increase your energy resilience. 
• The exact number of solar panels you need to charge your EV depends on your car’s energy efficiency, the distance you drive each day, solar panel efficiency, and the number of sunlight hours your location receives each day. 
• In most cases, you can fully charge your EV with anywhere between 6 to 12 solar panels, but the timing needed for a full charge may vary.
• You can choose to add more solar panels to your system to accommodate for your EV charging needs, or opt for other options such as a solar carport. 

Why charge an EV with solar panels?

Charging your electric vehicle or plug-in hybrid  with solar panels can maximize your cost savings, decrease your carbon footprint, and make you less dependent on increasingly expensive grid electricity. Let’s take a look at some reasons why charging your EV with solar panels makes sense. 

Maximize cost savings

In most places, it’s already cheaper to charge an EV with grid electricity than to refuel a gas-powered car. Charging your EV with solar power will take these savings even further. There are many ways to charge your EV, from grid power to generators or even windmills. But the most common methods include: 

• Using a public charger
• Using grid power at home
• Charging with solar panels. 

From these three options, solar power is the most cost-effective by far. Charging your electric car battery using solar power can cost half as much as using grid power, and nearly five times less than using a public charger. 

This is because residential solar power costs around 8 to 10c per kilowatt-hour (kWh) on average, compared to the national grid average of 16.54c per kWh. Over time, the savings from charging your EV battery at home can add up to be quite substantial. 

Increase sustainability of your EV

Many people switch to electric vehicles to reduce their reliance on fossil fuels. Charging your electric car with solar power takes that commitment a step further by reducing your dependence on the utility grid. Although grid power is gradually becoming cleaner, it still relies heavily on fossil fuels which release greenhouse gas emissions, or nuclear, which has its own environmental concerns. Solar power, on the other hand, is 100% renewable. This reduces your carbon footprint even more and makes your transition to electric driving even more sustainable.

Reduce grid reliance

Using home solar power to charge your EV makes you less dependent on the grid. This is especially valuable if you live in an area prone to outages or natural disasters. With a solar battery system, you can store excess power generated during the day and use it to charge your EV at night, on cloudy days, or even during blackouts – so you’re never stranded at home with a dead battery. 

See More: Should I Get Battery Storage for My Solar Energy System?

Seamless compatibility

Home EV chargers can be quite power-hungry, typically requiring a 220V circuit and demanding large amounts of electricity as quickly as possible. This can strain your home’s electrical system – especially if your wiring is older or in need of an upgrade. 

How much energy do you need to charge your EV at home?

The first thing to consider when solar charging an EV is how much energy your car will consume and how your solar system can meet that demand. Below, we provide a step-by-step process for calculating how much power your EV needs to charge.

Step 1: Assess your solar goals and system setup

Start by clarifying your goals. Do you plan to rely solely on solar power to charge your EV? Will you mainly be charging at night? If overnight charging is your priority, then you’ll need to install a battery storage system on your home to store solar energy generated during the day and discharge it at night in order to fill your car’s battery.

Most solar systems are connected to the grid, allowing you to offload excess energy you generate into the grid, and pull grid electricity when you need it, such as at night. If your current setup includes solar panels without a battery, it helps to know how much of your solar output your home is currently consuming. To do this, consider your utility bills. 

If you pay minimal utility bills or only pay for electricity at night, it’s likely that your solar system is producing more electricity than your home uses. This means you probably have excess power to dedicate to charging your EV, potentially reducing the amount of solar panels you’ll need to add for EV charging.

Step 2: Estimate your EV’s energy usage

Next, you want to consider how much extra demand charging your EV will add to your system. This will depend on your daily driving habits and vehicle’s efficiency. Here’s a formula you can use to calculate your EV’s energy requirements. 

Start with the number of miles you travel per day. If you’re unsure, you can use the national average of 37 miles as a baseline. 

Next, find your EV’s efficiency, measured in miles per kWH (mi/kWh). If you don’t have this figure you can calculate it by dividing the car’s miles per gallon equivalent (MPGe) by 33.705. For example, a Tesla Model Y Standard Range RQD has an efficiency of 129 MPGe. To find its mi/kWh you would divide 129 by 33.705 to get 3.82 miles per kWh. 

When you have your car’s efficiency rating, you can divide the number of miles traveled per day by your EV’s efficiency rating. So, if you travelled the national average of 37 miles per day with a Tesla Model Y, your formula would be: 

37 miles per day / 38.2 mi/kWh = 9.69 kWh per day. 

This means a Tesla Model Y uses about 9.69 kWh of electricity per day. With that figure, you can now calculate how many solar panels are needed to generate that amount. 

Read More: How Many Solar Panels Do I Need?

How many solar panels do you need to charge your EV?

The number of solar panels you need to charge your EV at home depends on the efficiency of your vehicle, your daily driving habits, the wattage of your solar panels, and the amount of sunlight your location receives. Let’s break the calculation down step-by-step, continuing with the Tesla Model Y as an example. 

Step 1: Understand your EV’s energy needs

This was covered in the section above. We’ve already calculated that the Tesla Model Y needs about 9.69 kWh of energy per day to travel 37 miles (the national average). This figure gives us the total amount of electricity your solar system needs to generate each day to cover your EV charging needs. 

Step 2: Calculate your solar panel output

The amount of energy a solar panel generates each day depends on its wattage and the average number of peak sun hours at your location. For the sake of this example, we’ll use a 360-watt solar panel and a conservative estimate of 4.5 sun hours per day. Here’s how to calculate a solar panel’s daily output in kWh:  

4.5 sun hours/day x 360 watts = 1,620 watt-hours/day, or 1.62 kWh/day per panel. 

Step 3: Find the number of panels

Finally, you want to calculate the number of solar panels you need to charge your EV. To do this, divide your EV’s daily energy needs by the daily energy output of a single solar panel. In our example, the formula would be: 

9.69 kWh/day divided by 1.62 kWh/panel/day = 5.98 panels. 

This means you’d need six 360-watt solar panels to fully charge a Tesla Model Y traveling 37 miles per day. Note that more efficient solar panels would have a higher power output, meaning you’d need less overall to charge your EV, and vice versa. 

Should you add more solar panels to charge your EV?

When people think of charging their EV through solar power, they usually consider adding more solar panels – either to their existing solar array or to a system they’re planning. While that’s an easy and popular option, it’s not the only option you have. You could also consider building a stand-alone off-grid system dedicated exclusively to charging your EV, like a solar carport. 

This option is especially appealing if you want to maximize solar energy production without impacting your home’s energy needs. Your solar carport could be designed with panels tilted at the right angle to match your location’s latitude for maximum sun exposure. This setup would provide the dual-benefit of being a highly efficient EV charging station as well as a protective structure for your car. 

Read More: Federal Solar Tax Credit: Everything You Need to Know

Should you install solar or buy the EV first?

The choice between installing solar panels or purchasing an EV first depends on your goals, budget, and personal priorities. If your main motivation is environmental, then it makes sense to install solar power first. This ensures both your home and EV are powered by clean, renewable energy from day one, reducing your dependence on the fossil-fuel reliant grid and lowering your overall carbon footprint. 

That said, many people think of EVs as a more practical purchase. Most people drive their cars on a daily basis, and an EV can start saving you money on fuel immediately while also reducing emissions compared to a gas-powered car. Compared to the immediacy of driving a flashy new EV, changing the way your home receives electricity might not feel as exciting or necessary. 

Ultimately, the choice between buying an EV or installing solar panels first is a matter of budget. If you can afford to invest in both, then pairing solar with an EV maximizes your sustainability impact. If not, then starting with one is still a meaningful step towards a greener future – and you can always add the other later.

Keep Reading: How to Pick the Best Home EV Charger for Your Electric Car

Summary: How many solar panels do you need to charge your EV?

The exact number of solar panels needed to charge an EV is different for everyone. Four major factors to consider include:

• Your EV’s fuel efficiency
• Number of miles you drive each day
• Solar panel wattage
• Average sun hours your location receives each day.  

Understanding these factors can help you calculate how much energy your solar system needs to generate each day to fully charge your EV. For most drivers, this translates to about 5 to 12 solar panels, depending on your specific circumstances. 

If you want personalized guidance on the number of solar panels needed to charge your electric vehicle, don’t hesitate to reach out to our team at Sun Valley Solar Solutions. We will be happy to explore your options when it comes to charging your EV with solar power, and we can even recommend car chargers based on your home and EV. Contact us now for a free consultation.